Preparation of polymer nanocomposites by dispersion destabilization

ABSTRACT

Nanocomposites may be produced by mixing dispersions of polymers and dispersions of clay minerals. After mixing, the dispersions may be destabilized with the addition of appropriate compounds. The flocculated solid material exhibits characteristics of a nanocomposite, such as exfoliation of the clay mineral platelets as indicated by x-ray diffraction analysis.

PRIORITY CLAIM

[0001] This application claims priority to U.S. Provisional PatentApplication No. 60/273,271 filed on Mar. 2, 2001 entitled “Preparationof Polymer Nanocomposites by Dispersion Destabilization.”

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention generally relates to a polymernanocomposite. More particularly, the invention relates to a polymernanocomposite formed from a mixture of a clay dispersion with a polymerdispersion.

[0004] 2. Description of the Relevant Art

[0005] There has been considerable interest in forming nanocompositesespecially by addition of clay minerals into polymeric materials. Clayminerals such as montmorillonite are composed of silicate layers with athickness of about 1 nanometer.

[0006] Incorporation of such layered materials in polymers result inproducts which may frequently be referred to as nanocomposites.Incorporating clay minerals in a polymer matrix, however, may not alwaysbe a straightforward process. Incorporating clay minerals may requireadditional manufacturing steps or additional capital equipment costs,especially if melt processing may be required. Some have tried toimprove the process of forming nanocomposites by increasing thecompatibility between the clay minerals and the organic polymers. Thus,it has been proposed to use lipophilic compounds, such as oniumcompounds, to treat the clay minerals to increase the compatibility ofthe clay minerals in a polymer as shown in U.S. Pat. No. 4,889,885, toUsuki et al. and U.S. Pat. No. 4,810,734 to Kawasumi et al, both ofwhich are incorporated herein by reference.

[0007] Another proposed method to improve incorporation of clay mineralsinto polymers is the use of emulsion polymerization. A dispersion isproduced having a layered silicate, a monomer, and a polymerizationinitiator. The monomer is polymerized to form the latex. Thispolymerization process results in a latex containing a layered materialintercalated with a polymer. This method is disclosed in U.S. Pat. No.5,883,173 to Elspass et al., which is incorporated herein by reference.However, the approaches to preparing nanocomposites, whether by meltprocessing, ionic additions, or emulsion polymerization, may provedifficult in controlling exfoliation and polymer molecular weight.Efficiency in emulsion polymerization may also be difficult to achieve.

SUMMARY OF THE INVENTION

[0008] In an embodiment, a clay mineral, such as, but not limited tosmectite clay minerals, may be intercalated with a polymer by mixing adispersion of a polymer in a liquid carrier and a dispersion of a claymineral in a liquid carrier to form a dispersion mixture. The dispersionmixture may be treated with a flocculating agent. A dispersion ofpolymer in a liquid carrier may be prepared by any of the meansavailable to those skilled in the art. In an embodiment, the polymericdispersion may be formulated by mixing a combination of a liquidcarrier, a surfactant, and a polymer. In an embodiment, a clay mineraldispersion may be produced by mixing a clay mineral with a liquidcarrier such that the clay mineral is dispersed in the liquid carrier. Asurfactant may be added when preparing a dispersion of a clay mineral inthe liquid carrier. The two dispersions may be subsequently mixedtogether to produce a dispersion mixture of the polymer and the claymineral. The dispersion mixture may then be flocculated by addition of aflocculating agent. Examples of flocculating agents may be, but are notlimited to, inorganic salts, double-layered metal hydroxides, quaternaryonium compounds, or an onium saturated clay mineral. An onium saturatedclay mineral may be defined as a clay mineral that has been treated witha quaternary onium compound added in excess of that required to meet theCation Exchange Capacity (CEC) of the clay mineral. In an embodiment, anon-layered clay mineral may be substituted in the aforementionedcompositions in place of a layered clay mineral.

[0009] The flocculated nanocomposite material may be separated from theliquid carrier using techniques such as, but not limited to, filtration,centrifugation, or evaporation. The nanocomposite may be formulated,compounded, and processed for use in applications such as, but notlimited to, plastic engineered parts, film, and fiber as well as rubberarticles such as tires, belts, and hoses.

[0010] The following terms are used throughout:

[0011] Flocculation as defined herein is the aggregation of colloidalparticles suspended in water.

[0012] Intercalation as defined herein is the movement of polymerbetween smectite layers, where the layers are separated, but the orderedrelationship between the layers is maintained. In pure examples ofintercalation, the interlayer spacing can be measured by X-raydiffraction.

[0013] Exfoliation as defined herein is the movement of polymer betweenthe smectite layers, where the layers are separated and the orderedrelationship between the layers is lost. In completely exfoliatedexamples, no X-ray diffraction results from the interlayer separations.

[0014] Nanocomposite as defined herein is a composition comprisinglayered inorganic particles in a polymer matrix.

DETAILED DESCRIPTION OF THE INVENTION

[0015] In an embodiment, a polymer dispersion may be prepared bydispersion of a polymer within a liquid carrier. The polymer dispersionmay be prepared by adding an amount of polymer, up to about 80% byweight of polymer, to the liquid carrier. The liquid carrier may beeither water, an organic solvent, or mixtures thereof. Polymers that maybe used include, but are not limited to, the following examples:polyester, polyurethane, polyvinyl chloride, styrene-butadiene, acrylicrubber, chlorosulfonated polyethylene rubber, fluoroelastomer,polyisoprene, polycarbonate resin, polyamide resin, polyolefin resin,thermoplastic resin or mixtures thereof. The polymer dispersion may besubjecting to a shearing process to fully disperse the polymericmaterial within the liquid carrier.

[0016] A clay mineral dispersion may be prepared by adding from about 1%to about 10% by weight of a clay mineral to a liquid carrier. The liquidcarrier may be either water, an organic solvent, or mixtures thereof.The clay mineral used may be naturally occurring or synthetic.Positively charged or negatively charged minerals may be used.Representative examples of negatively charged clay minerals useful inaccordance with an embodiment may be as follows:

[0017] Montmorillonite

(Si_(8−x)Al_(x))(Al_(4−y)(Ti, Fe, Mg)_(y)O₂₀(OH)₄R_(x+y) ⁺

[0018] where 0≦x≦0.4; 0.55≦y≦1.10 and R is selected from the groupconsisting of Na⁺, Li⁺, NH₄ ⁺, and mixtures thereof;

[0019] Hectorite

(Mg_(6−x)Li_(X))Si₈O₂₀(OH, F)₄R_(x) ⁺

[0020] where 0.57≦x≦1.15; and R is selected from the group consisting ofNa⁺, Li⁺, NH₄ ⁺, and mixtures thereof;

[0021] Saponite

(Si_(8−x)Al_(x))(Mg, Fe)₆O₂₀(OH)₄R⁺

[0022] where 0.58≦x≦1.84; and R is selected from the group consisting ofNa⁺, Li⁺, NH₄ ⁺, and mixtures thereof;

[0023] Stevensite

[Mg_(6−x)Si₈O₂O(OH)₄]R_(2x) ⁺

[0024] where 0.28≦x≦0.57; and R is selected from the group consisting ofNa⁺, Li⁺, NH₄ ⁺, and mixtures thereof.

[0025] Beidellite

[Al₄(Si_(8−x)Al_(x))O₂₀(OH)₄]R_(x) ⁺

[0026] where 0.55≦x≦1.10; and R is selected from the group consisting ofNa⁺, Li^(+, NH) ₄ ⁺, and mixtures thereof.

[0027] Positively charged minerals may also be used. Positively chargedminerals in accordance with an embodiment, may be, but are not limitedto, hydrotalcite or other double-layered mineral compounds. Arepresentative double-layered mineral compound may have the followingstructure:

[0028] Double-layered Metal Hydroxide

[M(II)_(1−x)M(III)_(x)(OH)₂]^(x+)(A^(n−) _(x/n))·mH₂O

[0029] wherein M is a metal with either a 2⁺ or 3⁺ charge, A is ananion, which may be a carbonate, sulfate, perchlorate, halogen, nitrate,transition metal oxide, or any one of many other negatively chargedions, and values of x may lie in the range of 0.1 to 0.5.

[0030] In some embodiments, the clay mineral compound may be chosenbased on the charge of the polymer used in the polymer dispersion. Whena negatively charged polymer is used, a negatively charged clay mineral(e.g., montmorillonite) may be used in the clay mineral dispersion.Alternatively if a positively charged polymer is used, a positivelycharged clay mineral (e.g. hydrotalcite) may be used in the clay mineraldispersion.

[0031] A clay mineral dispersion may be further processed by passing theclay mineral dispersion through a high shear mixer. This shearing stepmay be achieved by a homogenizing mill of the type wherein high-speedfluid shear of the slurry may be produced by passing the slurry at highvelocities through a narrow gap, across which a high pressuredifferential may be maintained. This type of action may be produced inthe well-known Manton-Gaulin (“MG”)device which is sometimes referred toas the “Gaulin homogenizer.” A description of the Manton-Gaulin mixermay be found in U.S. Pat. No. 4,664,842 to Knudson, Jr. et al, which isincorporated herein by reference. Other shearing equipment may be used,provided sufficient shear is imparted to the system to disperse the claymineral within the liquid carrier system.

[0032] The polymer dispersion may be mixed with the clay mineraldispersion to form a clay-polymer dispersion mixture. Sufficient shearmay be added to produce a well-blended mixture. The amount of polymerdispersion and clay mineral dispersions to be mixed may vary based uponthe solids contents of both the mineral dispersion and the polymerdispersion. The amount of polymer and clay mineral dispersions to bemixed may also vary based upon the amount of clay mineral to beintercalated in the polymer. The amount of polymer and clay mineraldispersions mixed may be adjusted such that the clay mineral is presentin an amount of up to about 90% by weight of the final polymer product.Polymer products having a clay mineral content of up to about 30% byweigh of the polymer product are particularly useful in someapplications. For use with latex and other rubber polymers, polymerproducts having a clay mineral content of up to about 10% by weight ofthe polymer product are particularly useful.

[0033] A flocculating agent may be added to flocculate the clay-polymerdispersion mixture. Up to about 10% by weight flocculating agent may beadded to flocculate the clay-polymer dispersion mixture. Flocculatingagents include, but are not limited to, organic salts, inorganic salts,and mineral compounds. Examples of organic salts include, but are notlimited to, compounds such as quaternary ammonium compounds, phosphoniumcompounds, sulfonium compounds. Other organic salts include, but are notlimited to, primary, secondary and tertiary amine salts. Inorganic saltsinclude, but are not limited to, any suitable Group I or Group II maingroup metal cation or any suitable transition metal cation that providessufficient ionic charge to flocculate the dispersions. Any anion thatprovides sufficient solubility of the inorganic compound in the liquidcarrier may be used. Examples of anions include, but are not limited to,chloride, bromide, iodide, sulfate, nitrate, perchlorate, chlorate, orphosphate. Examples of inorganic salts include, but are not limited to,calcium chloride, magnesium chloride, sodium chloride, potassiumchloride, or lithium chloride. Mineral compounds include, but are notlimited to, hydrotalcite.

[0034] In some embodiments, flocculating agents are charged molecules.The charge of the flocculent used may be opposite the charge of thepolymer. For example, latex polymers are generally negatively chargeddue to the typical manufacturing processes used to manufacture latexmaterials. It has been found that a flocculant having a positive charge(e.g., a quaternary ammonium compound or hydrotalcite) is most effectivein forming the polymer nanocomposite. Alternatively, a flocculent havinga negative charge (e.g., montmorillonite) is preferred for inducingflocculation of positively charged polymers.

[0035] In some embodiments, quaternary ammonium compounds describedherein may be made from natural oils such as tallow, soy, coconut andpalm oil. Aliphatic groups of a quaternary ammonium compound may bederived from other naturally occurring oils including various vegetableoils, such as corn oil, coconut oil, soybean oil, cottonseed oil, castoroil and the like, as well as various animal oils or fats (e.g., tallow).The aliphatic groups may be petrochemically derived from, for example,alpha olefins. Representative examples of useful branched, saturatedradicals may include 12-methylstearyl and 12-ethylstearyl. Examples ofuseful aromatic groups, may be benzyl and substituted benzyl moieties,including benzyl and benzylic-type materials derived from benzylhalides, benzhydryl halides, trityl halides, α-halo α-phenylalkaneswherein the alkyl chain has from 1 to 30 carbon atoms. For example,1-halo-1-phenyloctadecane and substituted benzyl moieties, such as thosederived from ortho-, meta- and para-chlorobenzyl halides,para-methoxybenzyl halides, ortho-, meta-, and para-nitrilobenzylhalides, and ortho-, meta-, and para-alkylbenzyl halides wherein thealkyl chain includes from 1 to 30 carbon atoms; and fused ringbenzyl-type moieties, such as those derived from2-halomethylnaphthalene, 9-halomethylanthracene and9-halomethylphenanthrene, wherein the halo group includes chloro, bromo,or any other such group which may serve as a leaving group in thenucleophilic attack of the benzyl type moiety such that the nucleophilereplaces the leaving group on the benzyl type moiety.

[0036] Examples of other aromatic groups may include aromatic-typesubstituents such as phenyl and substituted phenyl, N-alkyl andN,N-dialkyl anilines, wherein the alkyl groups may have between 1 and 30carbon atoms; ortho-, meta-, and para-nitrophenyl, ortho-, meta- andpara-alkyl phenyl, wherein the alkyl group includes between 1 and 30carbon atoms, 2-, 3-, and 4-halophenyl wherein the halo group is definedas chloro, bromo, or iodo, and 2-, 3-, and 4-carboxyphenyl and estersthereof, where the alcohol of the ester may be derived from an alkylalcohol, wherein the alkyl group comprises between 1 and 30 carbonatoms, aryl such as phenol, or aralkyl such as benzyl alcohols; andfused ring aryl moieties such as naphthalene, anthracene, andphenanthrene.

[0037] Examples of quaternary ammonium compounds include, but are notlimited, to compounds having the following structure:

[0038] wherein R₁ is an alkyl group having about 12 to about 22 carbonatoms, wherein R₂, R₃ and R₄ are alkyl groups containing 1 to about 22carbon atoms, aryl groups or arylalkyl groups containing 7 to about 22carbon atoms and wherein M is chloride, bromide, iodide, nitrite,hydroxide, nitrate, sulfate, methyl sulfate, halogenated methyl groupsor C₁ to C₁₈ carboxylate. The following structures are non-limitingexamples of quaternary ammonium compounds:

[0039] Dimethyl dihydrogenated tallow ammonium chloride (2M2HT):

[0040] wherein HT=hydrogenated tallow;

[0041] Methyl bis[2-hydroxyethyl] stearyl ammonium chloride (M2HES):

[0042] Dimethyl dibehenyl ammonium chloride;

[0043] Methyl Tris[hydrogenated tallow alkyl] chloride;

[0044] wherein HT=hydrogenated tallow.

[0045] Hydrogenated tallow alkyl(2-ethylhexyl)dimethyl ammoniummethylsulfate, (Arquad ® HTL8-MS, Akzo Chemical);

[0046] wherein HT=hydrogenated tallow, and X⁻ is methyl sulfate.

[0047] Other non-limiting examples of alkyl quaternary ammonium saltsemployed for flocculating the dispersion may include alkyl quaternaryammonium salts containing the same or different straight and/orbranched-chain saturated and/or unsaturated alkyl groups of about 1 toabout 20 carbon atoms. The salt moiety may include chloride, bromide,methylsulfate, nitrate, hydroxide, acetate, phosphate or mixturesthereof. In some embodiments, the alkyl quaternary ammonium salts mayinclude, but are not limited to, dimethyl di(hydrogenated tallow)ammonium chloride, methylbenzyl di(hydrogenated tallow) ammoniumchloride, dimethylbenzyl hydrogenated tallow ammonium chloride,(bishydroxyethyl) methyl tallow ammonium chloride, dimethyl hydrogenatedtallow-2-ethylhexyl ammonium methylsulfate, or mixtures thereof.

[0048] Examples of amine salts that may be used as a flocculant mayinclude, but are not limited to, compounds having the followingstructure:

[0049] wherein R₁, R₂, and R₃ may be independently hydrogen, alkyl,aryl, or alkylaryl groups. The alkyl, aryl, or alkylaryl groups mayinclude carbon moieties of about 1 to about 20 carbon atoms and X may bechloride, bromide, iodide, nitrite, nitrate, hydroxide, sulfate,sulfite, phosphate or other suitable anionic substituents.

[0050] Examples of amine compounds that may be used as the amine saltsmay be, but are not limited to salts of the following amines:methylamine, ethylamine, propylamine, isopropylamine, butylamine,isobutylamine, sec-butylamine, tert-butylamine, cyclohexylamine,benzylamine, aniline, p-toluidine, p-anisidine, dimethylamine,diethylamine, dipropylamine, N-methylaniline, trimethylamine,triethylamine, tripropylamine, and N,N-dimethylaniline. Further examplesof amine compounds that may be used as the amine salts may be, but arenot limited to, the following: dodecyl dimethyl amine, octadecyldimethyl amine, dodecyl amine, octadecyl amine, dodecyl methyl amine,and octadecyl methyl amine.

[0051] A flocculated clay-polymer dispersion may be further processed byfiltration, centrifugation, or drying. In an embodiment, the flocculatedclay-polymer dispersion may be separated from the liquid carrier byfiltration to form a filtercake. The filtercake may be dried to achievereduction of the water content to less than about 50%. The nanocompositemay be further processed using rollers, mixers, or milled to break apartthe filtercake. The resulting particles may be further processed intonon-limiting examples such as plastic engineered parts, film, fiber, andrubber articles such as tires, belts and hoses using known processingmethods.

[0052] The clay mineral may be treated with an onium compound prior toforming a mineral clay dispersion. Examples of onium compounds include,but are not limited to, quaternary ammonium compounds, phosphoniumcompounds and sulfonium compounds. In an embodiment a clay mineraldispersion may be prepared in the following manner. A clay mineral maybe added to an aqueous carrier to produce a slurry having between about1% by weight to about 10% by weight of clay mineral. An onium compoundmay be added to the slurry. The amount of onium compound may be greaterthan 1 and up to about 3 times the Cation Exchange Capacity (CEC) of theclay mineral. The slurry may be subjected to a high shear treatment inany number of shearing mills. One example of a shearing mill may be theManton-Gaulin mill as previously described. After subjecting the claymineral slurry to high shear, the resulting clay mineral dispersion maybe mixed with a polymer dispersion as described before. Moderate shearmay be used to achieve mixing of the two dispersions. A moderate shearmay be supplied, for example, by a Cowles blender. The resultingclay-polymer dispersion may be further processed as described herein.

[0053] An onium compound (e.g., a quaternary ammonium compound) may beadded in excess of that required to meet the Cation Exchange Capacity(CEC) of the clay mineral. It has been found that such compounds may notrequire the addition of a flocculating agent after the clay mineraldispersion is mixed with the polymer dispersion. It is believed thatclay minerals treated with excess onium compounds may include asufficient amount of onium compound such that any onium compound that ispresent, but not bound to the clay mineral, may serve as a flocculatingagent. That is, while a portion of the onium compound is intercalatedwithin the clay mineral, some of the excess onium compounds remainsdispersed or dissolved in the liquid carrier. As opposed to thepreviously described embodiment, the flocculating agent, (e.g., theonium compound) is thus added prior to forming the clay-polymerdispersion, rather than after.

[0054] Mineral compounds may also be used as a flocculating agent. In anembodiment, a polymeric dispersion and a clay mineral dispersion may beprepared as previously described. The clay mineral dispersion may beadded to the polymeric dispersion without causing flocculation. Thepolymeric dispersion/clay mineral dispersion mixture may then becontacted with about 1% to about 10% by weight of a mineral compound(e.g., hydrotalcite) to cause flocculation of the polymeric dispersion.Following flocculation, the resulting nanocomposite may be processed asdescribed in an earlier section.

[0055] In one embodiment, the clay mineral dispersion is added to thepolymer dispersion to form a clay-polymer dispersion. Alternatively, thepolymer dispersion may be added to the clay dispersion to form theclay-polymer dispersion.

[0056] In an embodiment, a polymer dispersion and a clay mineraldispersion may be prepared separately as described earlier. Thesedispersions may be mixed with sufficient shear to produce a clay-polymerdispersion as described earlier. To the clay-polymer dispersion, withmixing, may be added an inorganic salt at about 1% to about 20% byweight of solution such that the clay-polymer dispersion may beflocculated. The produced nanocomposite may be processed as described inthe previous sections.

[0057] The polymer and clay dispersions in the embodiments describedherein may include a range of particle sizes. The dispersions mayinclude finely divided particles distributed throughout a bulk substancewhere the particles may be the disperse or internal phase and the bulksubstance may be the continuous or external phase. The polymer and claysizes may range from about 0.05 microns to about 5.0 microns. Thisparticle size range may produce a colloidal dispersion. Polymer and claydispersions may be, but are not limited to, colloidal dispersions. Otherdispersions with a different range of particle sizes may be included inother embodiments.

[0058] While the aforementioned embodiments used layered clay mineralsin dispersions and as flocculants, non-layered clay minerals may beutilized as well. Examples of non-layered clay minerals that may be usedinclude, but are not limited to, sepiolite or attapulgite.

[0059] X-ray diffraction may be used to determine the extent ofexfoliation, or separation, of the mineral layers in the nanocomposite.In powder x-ray diffraction, the D₀₀₁ peak may be monitored and distanceof the spacing between the platelets may be inferred. X-ray diffractiondata may be used to determine intercalation and disorder of clay mineralparticles incorporated within the polymer. Platelet spacing values mayrange from 1-2 Å in an untreated clay mineral. In clays where theplatelets are so well separated, such as in a nanocomposite, the D₀₀₁peak may be absent in the x-ray scan.

[0060] In some embodiments, a surfactant may be added to the polymerdispersion to aid in dispersion of the polymer. Surfactants that may beused include amphoteric, anionic, cationic, and non-ionic. A surfactantmay be added in an amount from about 1% to about 20% by weight ofpolymer.

[0061] The nanocomposites herein described, may be mixed with othermaterials to produce a number of different products or articles. Thenanocomposite may be formulated, for example, into automobile tires. Thenanocomposite may be added to impart improved performance of theautomobile tire on ice by minimizing reinforcing performance of a treadrubber, while still improving the traction force by the elimination ofhydroplaning and increasing the area of contact with a road surface.

[0062] A rubber composition formed with the nanocomposites may exhibitexcellent hydrophobic and water repellency properties. The rubbercomposition, when used in automobile tires, may reduce water depositionon the surface of the tread, thereby increasing the area of contactbetween a tire and road surface. U.S. Pat. No. 6,147,151 to Fukumoto, etal., which is incorporated herein by reference, further describes tireproduction.

[0063] Paints may also be formulated with the nanocomposites describedherein to improve desirable paint characteristics such as minimizedsagging, luster, durability, thixotropy, and solids suspension. Thenanocomposites described herein may be used in those specialty paintformulations especially designed to paint the polymeric materials ofautomobile bumpers and the like. U.S. Pat. No. 6,133,374 to Nam, et al.,which is incorporated herein by reference, further describes the use ofnanocomposites in paint formulations.

[0064] The nanocomposites described herein may, for example, be used inmelt extrusion of the nanocomposite into film. Formulation may beaccomplished by feeding solid polymer to an extruder in which thepolymer may be heated to a temperature above its melting point. Arotating screw pushes the polymer and the resulting viscous polymer meltthrough the extruder barrel into a die in which the polymer may beshaped to the desired form. The resulting extrudate may either bequenched or allowed to cool slowly to temperatures below the meltingpoint, causing the extrudate to rigidify and assume the shape of the dieorifice. For cast film, a gapped coat hanger die may be used to lay amelt of modified polymerized organic system onto a roller. The film maythen be fed through a nip roller and onto a take-up roll.

[0065] Film may also be produced as a blown film by feeding the melt ofthe nanocomposites through an annular die, blowing air into the insideof the bubble, then collapsing the bubble and collecting on a roll-upspool. The film may be either a monolayer or multiple layer material.

[0066] In melt extrusion of polymer resins there may be flow regimeswhere anomalous flow behavior occurs leading to surface imperfections onthe extrudate surfaces. Such imperfections, commonly called meltfractures, appear in different forms. The so-called “sharkskin” fracturemay occur at lower shear rates and may appear as a finely-structured anduniform roughness. In a blown-film extrusion, sharkskin fractures mayappear as an undesirable herringbone pattern, reducing clarity andgiving a dull surface. At various shear rates, flow may becomeunpredictable such that alternating bands of glossy surface andsharkskin fracture appear. This behavior may be especially undesirablein wire coating and in tube and pipe extrusions, as well as in blownfilm processes.

[0067] There may be several methods for eliminating surface meltfracture under commercial film fabrication conditions. These may beaimed at reducing the shear stresses in the die and may includeincreasing the melt temperature, modifying the die geometry, or the useof slip additives in the resin to reduce friction at the wall. U.S. Pat.No. 3,125,547 to Blatz, U.S. Pat. No. 4,552,712 to Ramamurthy, and U.S.Pat. No. 5,089,200 to Chapman, Jr., et al., all of which areincorporated herein by reference further describe polymer film extrusionprocessing methods.

[0068] In production of fibers, or with injection molding or blowmolding, the nanocomposites may impart favorable characteristics tothose materials and processes. For example, fibers may exhibit increasedtensile or flexural strength. The nanocomposites may also improve theextrusion of the fibers similar to the elimination of melt fractures incommercial films. Injection molding processes may exhibit improvementsin form release and more accurate replication of the molded product tothe form. Blow molding processes may exhibit improved surface structurefeatures.

[0069] The following examples serve to illustrate methods of producing ananocomposite by the previous embodiments. The examples should not beconsidered limiting.

EXAMPLE 1

[0070] To 100 g of an approximately 50% solids by weight of Good-RiteSB-0738 (a latex polymer available from B. F. Goodrich), was added, withstirring, 100 g of a 3.06% by weight aqueous clay slurry of Cloisite®(Southern Clay Products). To the stirred mixture was added 4.8 grams ofhydrogenated tallow alkyl(2-ethylhexyl)dimethyl ammonium methylsulfate,(Arquad ® HTL8-MS, Akzo Chemical). The dispersion mixture flocculated,was separated from the water by filtration and the solids were dried inan oven at about 50° C. An x-ray diffraction analysis of the formednanocomposite was run. The D₀₀₁ peak was absent indicating highexfoliation of the clay material in the polymer.

EXAMPLE 2

[0071] Example 2 was conducted as Example 1 except that Good-RiteSB-1168 (a latex polymer available from B. F. Goodrich) was utilized.The dispersion mixture flocculated. The D₀₀₁ peak was present andindicated smectite clay platelet spacing of about 36 Å.

EXAMPLE 3

[0072] Example 3 was conducted as Example 1 except that Good-RiteSB-1177 (a latex polymer available from B. F. Goodrich) was utilized.The dispersion mixture flocculated. The D₀₀₁ peak was present andindicated smectite clay platelet spacing of about 38 Å.

EXAMPLE 4

[0073] A filtercake of an organoclay was prepared in the following way.A montmorillonite clay was exchanged with hydrogenated tallowalkyl(2-ethylhexyl)dimethyl ammonium methylsulfate, (Arquad ® HTL8-MS,Akzo Chemical) at 130 MER. MER is a measure of milliequivalent ratio(MER), providing the relationship between the amount of a quaternaryonium compound added to a clay based upon the cation exchange capacityof the clay. The slurry was filtered and the filtercake was processed bymilling before use. The solids content of the filtercake was 47.40%. To100 grams of Good-Rite SB-1168 was added 12.66 grams of the processedfiltercake. A high speed disperser was employed for dispersion of thefiltercake into Good-Rite SB-1168. The dispersion mixture flocculated.The solids were isolated and an x-ray diffraction analysis was conductedon the resulting nanocomposite. The D₀₀₁ peak was present and indicatedsmectite clay platelet spacing of about 28 Å.

EXAMPLE 5

[0074] A mixture of 97 g of deionized water and 3 grams of hydrotalcitewere subjected to a high energy disperser. After about 5 minutes of highshear the viscosity of the solution was about 250-500 centipoise (cps).After about four hours, the viscosity increased to about that of a 3%montmorillonite slurry. The slurry was then passed through a hand pumphomogenizer and the viscosity reverted back to a water thin viscosity.To 78.7 grams of the hydrotalcite dispersion was slowly added, withstirring, 60.6 grams of a 70% solids by weight of Goodyear LPF-6758 (astyrene-butadiene latex, available from Goodyear). When 26.2 grams ofGoodyear LPF-6758 were added, the dispersion mixture flocculated, andthe remainder of Goodyear LPF-6758 was added. A sample was prepared forx-ray diffraction. The D₀₀₁ peak was absent, indicating high exfoliationof the hydrotalcite in the polymer.

EXAMPLE 6

[0075] 40 grams of the aqueous hydrotalcite dispersion described inExample 5 was slowly added to 130 grams of Goodyear LPF-6758. Thedispersion mixture flocculated. The solids were prepared for x-raydiffraction analysis. The D₀₀₁ peak indicated spacing of about 39.9 Å.

EXAMPLE 7

[0076] 130 grams of a 3% aqueous montmorillonite slurry was added withstirring to 100 grams of Goodyear LPF-6758. To this mixture was added,with stirring, 57.8 grams of the aqueous hydrotalcite dispersiondescribed in Example 5. The dispersion mixture flocculated and thesolids prepared for x-ray diffraction analysis. The D₀₀₁ peak wasabsent, indicating high exfoliation of the clay mineral in the polymer.

EXAMPLE 8

[0077] A 3% solids aqueous Cloisite® dispersion was prepared with anexcess of hydrogenated tallow alkyl(2-ethylhexyl)dimethyl ammoniummethylsulfate, (Arquad ® HTL8-MS, Akzo Chemical) to produce a 125 MERorganoclay. The organoclay was passed through a Manton-Gaulinhomogenizer at a setting of about 4,500 psig. To 100 grams of GoodyearLPF-6758 was added, with stirring, 180.7 grams of the aqueous Cloisite®dispersion. The dispersion mixture flocculated. The solids were preparedfor x-ray diffraction analysis. The D₀₀₁ peak indicated spacing of theclay platelets of about 39.2 Å.

EXAMPLE 9

[0078] A 3.06% by weight aqueous organoclay slurry was made and passedthrough the Manton-Gaulin homogenizer at a setting of about 4,500 psig.The organoclay was a 125 MER organoclay with hydrogenated tallowalkyl(2-ethylhexyl)dimethyl ammonium methylsulfate, (Arquad ® HTL8-MS,Akzo Chemical). To 100 grams of Goodyear LPF-6758 was added, slowly andwith stirring, 181.2 grams of the organoclay dispersion. A flock formedafter 3 minutes of shearing. The solids produced were prepared for x-raydiffraction analysis. The D₀₀₁ peak indicated spacing of the clayplatelets of about 37.1 Å.

EXAMPLE 10

[0079] About 50 grams of the nanocomposite produced in Example 9 was fedinto a Brabender mixer over a period of two minutes and mixed for anadditional 5 minutes at 150° C. and at 60 rpm. The Brabender torque wasmeasured during the mixing. The torque initially increased to about 36.1Nm, and remained at that level during the 5 minute mixing. The materialwas removed and hot pressed for 5 minutes at 150° C. An x-raydiffraction analysis of the material was run. The D₀₀₁ peak was absent,indicating high exfoliation of the clay in the polymer.

EXAMPLE 11

[0080] This example is a scale-up of Example 9. To 400 grams of GoodyearLPF-6758 in a one gallon container was added, over a 5 minute period andutilizing a high speed disperser for mixing, 724 grams of the 125 MERorganoclay dispersion produced in Example 9. After all of the organoclaydispersion was added, mixing was continued for an additional 3 minutes.The mixture flocculated. An x-ray diffraction analysis of the materialwas run. The D₀₀₁ peak indicated spacing of the clay platelets of about39.3 Å.

EXAMPLE 12

[0081] Example 12 is a control for comparison purposes. It is an aqueousdispersion 125 MER hydrogenated tallow alkyl(2-ethylhexyl)dimethylammonium methylsulfate, (Arquad ® HTL8-MS, Akzo Chemical) treatedmontmorillonite clay. An x-ray diffraction analysis of the material wasrun. The D₀₀₁ peak indicated spacing of the clay platelets of about 25.6Å.

EXAMPLE 13

[0082] Example 13 is a control for comparison purposes. It is a drydispersion 125 MER of hydrogenated tallow alkyl(2-ethylhexyl)dimethylammonium methylsulfate, (Arquad ® HTL8-MS, Akzo Chemical) treatedmontmorillonite clay. An x-ray diffraction analysis of the material wasrun. The D₀₀₁ peak indicated spacing of the clay platelets of about 23.7Å.

EXAMPLE 14

[0083] Example 14 is a dried hydrotalcite. An x-ray diffraction analysisof the material was run. The D₀₀₁ peak indicated spacing of thehydrotalcite platelets of about 8.6 Å.

[0084] Further modifications and alternative embodiments of variousaspects of the invention will be apparent to those skilled in the art inview of this description. Accordingly, this description is to beconstrued as illustrative only and is for the purpose of teaching thoseskilled in the art the general manner of carrying out the invention. Itis to be understood that the forms of the invention shown and describedherein are to be taken as the presently preferred embodiments. Elementsand materials may be substituted for those illustrated and describedherein, parts and processes may be reversed, and certain features of theinvention may be utilized independently, all as would be apparent to oneskilled in the art after having the benefit of this description of theinvention. Changes may be made in the elements described herein withoutdeparting from the spirit and scope of the invention as described in thefollowing claims. TABLE 1 Platelet Exfoliation Measured by D₀₀₁ Spacingas a Function of Polymer and Clay Mineral Utilized Clay mineral typeamount in grams Example Polymer, amount in grams and percent solids D₀₀₁Spacing in ID and percent solids content content Flocculant Angstroms 1Good-Rite SB-0738 Cloisite 100 g 4.8 g HTL8 Absent 100 g 50% 3.06% 2Good-Rite SB-1168 Cloisite 100 g 4.8 g HTL8 36   100 g 50% 3.06% 3Good-Rite SB-1177 Cloisite 100 g 4.8 g HTL8 38   100 g 50% 3.06% 4Good-Rite SB-1168 130 MER MMT — 28   100 g 50% 12.66 g 5 GoodyearLPF-6758 Hydrotalcite 78.7 g — Absent 100 g 70% 3% 6 Goodyear LPF-6758Hydrotalcite 40 g — 39.9 130 g 70% 3% 7 Goodyear LPF-6758 MMT 130 g 3%Hydrotalcite 57.8 g Absent 100 g 70% 3% hydrotalcite 8 Goodyear LPF-6758125 MER HTL8 — 39.2 100 g 70% MMT subjected to MG 180.7 g 9 GoodyearLPF-6758 125 MER HTL8 — 37.1 100 g 70% MMT subjected to MG 181.2 g 11 Goodyear LPF-6758 125 MER HTL8 — 39.3 400 g 70% MMT subjected to MG 724g Controls — 125 MER HTL8 — 25.6 12  MMT subjected to MG aqueousdispersion 13  — Dry powder — 23.7 prepared by adding 125 MER HTL8 toMMT subjected to MG 14  — Hydrotalcite —  8.6

What is claimed is:
 1. A method of making a polymer nanocompositecomprising: combining a polymer dispersion with a clay mineraldispersion to form a clay-polymer dispersion; adding a flocculatingagent to the clay-polymer dispersion mixture to form the polymernanocomposite.
 2. The method of claim 1, further comprising forming apolymer dispersion by adding a polymer to a liquid carrier.
 3. Themethod of claim 1, further comprising forming a clay mineral dispersionby adding a clay mineral to a liquid carrier.
 4. The method of claim 1,wherein the polymer dispersion comprises a latex.
 5. The method of claim1, wherein the polymer dispersion comprises a styrene-butadiene.
 6. Themethod of claim 1 wherein the polymer dispersion comprises apolyurethane dispersion.
 7. The method of claim 1 wherein the polymerdispersion comprises polyvinyl chloride, an acrylic rubber, abutyl-containing polymer, a chlorosulfonated polyethylene rubber, afluoroelastomer, or a polyisoprene.
 8. The method of claim 1 wherein thepolymer dispersion comprises a negatively charged polymer and whereinthe flocculating agent comprises a positively charged compound.
 9. Themethod of claim 1 wherein the polymer dispersion comprises a positivelycharged polymer and wherein the flocculating agent comprises anegatively charged compound.
 10. The method of claim 1, wherein thepolymer dispersion comprises a polymer and a surfactant dispersed in aliquid carrier.
 11. The method of claim 1, wherein the polymerdispersion comprises up to about 80% by weight of the polymer.
 12. Themethod of claim 1, further comprising forming the polymer dispersion bysubjecting a mixture of the polymer in the first liquid carrier to ashearing process.
 13. The method of claim 1, wherein the clay mineraldispersion comprises montmorillonite.
 14. The method of claim 1, whereinthe clay mineral dispersion comprises bentonite.
 15. The method of claim1, wherein the clay mineral dispersion comprises hectorite, saponite,attapulgite, beidelite, stevensite, sauconite, nontronite, Laponite, orsepiolite.
 16. The method of claim 1, wherein the clay mineraldispersion comprises hydrotalcite.
 17. The method of claim 1, whereinthe clay mineral dispersion comprises between about 1 to about 10% byweight of the clay mineral.
 18. The method of claim 1, furthercomprising forming the clay dispersion by subjecting a mixture of theclay mineral in the second liquid carrier to a high shear process. 19.The method of claim 1, wherein the clay-polymer dispersion comprises upto about 90% by weight of clay mineral with respect to the weight ofpolymer in the clay-polymer dispersion.
 20. The method of claim 1,wherein the clay-polymer dispersion comprises up to about 30% by weightof clay mineral with respect to the weight of polymer in theclay-polymer dispersion.
 21. The method of claim 1, wherein theclay-polymer dispersion comprises up to about 10% by weight of claymineral with respect to the weight of polymer in the clay-polymerdispersion.
 22. The method of claim 1 wherein the flocculating agentcomprises an organic salt.
 23. The method of claim 1 wherein theflocculating agent comprises a quatemnary ammonium compound.
 24. Themethod of claim 1 wherein the flocculating agent comprises a quaternaryammonium compound having the structure:

wherein R₁, R₂, R₃, and R₄ are independently alkyl groups, aryl groupsor arylalkyl groups, and wherein at least one of R₁, R₂, R₃, or R₄ is analiphatic group derived from a naturally occurring oil.
 25. The methodof claim 1 wherein the flocculating agent comprises an inorganic salt.26. The method of claim 1 wherein the flocculating agent comprises aGroup I metal salt.
 27. The method of claim 1 wherein the flocculatingagent comprises a Group II metal salt.
 28. The method of claim 1 whereinthe flocculating agent comprises a mineral compound.
 29. The method ofclaim 1, wherein the flocculating agent comprises between about 1% toabout 10% by weight of the clay-polymer dispersion.
 30. A polymernanocomposite prepared by the method comprising: combining a polymerdispersion with a clay mineral dispersion to form a clay-polymerdispersion; adding a flocculating agent to the clay-polymer dispersionmixture to form the polymer nanocomposite.
 31. The polymer nanocompositeof claim 30, wherein the method further comprises forming a polymerdispersion by adding a polymer to a liquid carrier.
 32. The polymernanocomposite of claim 30, wherein the method further comprises forminga clay mineral dispersion by adding a clay mineral to a liquid carrier.33. The polymer nanocomposite of claim 30, wherein the polymerdispersion comprises a latex.
 34. The polymer nanocomposite of claim 30,wherein the polymer dispersion comprises a styrene-butadiene.
 35. Thepolymer nanocomposite of claim 30, wherein the polymer dispersioncomprises a polyurethane dispersion.
 36. The polymer nanocomposite ofclaim 30, wherein the polymer dispersion comprises polyvinyl chloride,an acrylic rubber, a butyl-containing polymer, a chlorosulfonatedpolyethylene rubber, a fluoroelastomer, or a polyisoprene.
 37. Thepolymer nanocomposite of claim 30, wherein the polymer dispersioncomprises a negatively charged polymer and wherein the flocculatingagent comprises a positively charged compound.
 38. The polymernanocomposite of claim 30 wherein the polymer dispersion comprises apositively charged polymer and wherein the flocculating agent comprisesa negatively charged compound.
 39. The polymer nanocomposite of claim30, wherein the polymer dispersion comprises a polymer and a surfactantdispersed in a liquid carrier.
 40. The polymer nanocomposite of claim30, wherein the polymer dispersion comprises up to about 80% by weightof the polymer.
 41. The polymer nanocomposite of claim 30, wherein themethod further comprises forming the polymer dispersion by subjecting amixture of the polymer in the first liquid carrier to a shearingprocess.
 42. The polymer nanocomposite of claim 30, wherein the claymineral comprises montmorillonite.
 43. The polymer nanocomposite ofclaim 30, wherein the clay mineral comprises bentonite.
 44. The polymernanocomposite of claim 30, wherein the clay mineral comprises hectorite,saponite, attapulgite, beidelite, stevensite, sauconite, nontronite,Laponite, or sepiolite.
 45. The polymer nanocomposite of claim 30,wherein the clay mineral comprises hydrotalcite.
 46. The polymernanocomposite of claim 30, wherein the clay mineral dispersion comprisesbetween about 1 to about 10% by weight of the clay mineral.
 47. Thepolymer nanocomposite of claim 30, wherein the method further comprisesforming the clay dispersion by subjecting a mixture of the clay mineralin the second liquid carrier to a high shear process.
 48. The polymernanocomposite of claim 30, wherein the clay-polymer dispersion comprisesup to about 90% by weight of clay mineral with respect to the weight ofpolymer in the clay-polymer dispersion.
 49. The polymer nanocomposite ofclaim 30, wherein the clay-polymer dispersion comprises up to about 30%by weight of clay mineral with respect to the weight of polymer in theclay-polymer dispersion.
 50. The polymer nanocomposite of claim 30,wherein the clay-polymer dispersion comprises up to about 10% by weightof clay mineral with respect to the weight of polymer in theclay-polymer dispersion.
 51. The polymer nanocomposite of claim 30,wherein the flocculating agent comprises an organic salt.
 52. Thepolymer nanocomposite of claim 30, wherein the flocculating agentcomprises a quaternary ammonium compound.
 53. The polymer nanocompositeof claim 30, wherein the flocculating agent comprises a quaternaryammonium compound having the structure:

wherein R₁, R₂, R₃, and R₄ are independently alkyl groups, aryl groupsor arylalkyl groups, and wherein at least one of R₁, R₂, R₃, or R₄ is analiphatic group derived from a naturally occurring oil.
 54. The polymernanocomposite of claim 30, wherein the flocculating agent comprises aninorganic salt.
 55. The polymer nanocomposite of claim 30, wherein theflocculating agent comprises a Group I metal salt.
 56. The polymernanocomposite of claim 30, wherein the flocculating agent comprises aGroup II metal salt.
 57. The polymer nanocomposite of claim 30, whereinthe flocculating agent comprises a mineral compound.
 58. The polymernanocomposite of claim 30, wherein the flocculating agent comprisesbetween about 1% to about 10% by weight of the clay-polymer dispersion.59. A method of making a polymer nanocomposite comprising: forming aclay mineral dispersion by adding a clay mineral and an onium compoundto a liquid carrier, wherein the onium compound is present in excess ofthe cation exchange capacity of the clay mineral such that a portion ofthe onium compound present is not bound to the clay mineral; combining apolymer dispersion with the clay mineral dispersion to form the polymernanocomposite.
 60. The method of claim 59, wherein the onium compoundcomprises a quaternary ammonium compound.
 61. The method of claim 59wherein the onium compound comprises a quaternary ammonium compoundhaving the structure:

wherein R₁, R₂, R₃, and R₄ are independently alkyl groups, aryl groupsor arylalkyl groups, and wherein at least one of R₁, R₂, R₃, or R₄ is analiphatic group derived from a naturally occurring oil.
 62. The methodof claim 59, wherein the amount of onium compound is up to about 3 timesthe cation exchange capacity of the clay mineral.
 63. The method ofclaim 59, further comprising forming a polymer dispersion by adding apolymer to a liquid carrier.
 64. The method of claim 59, wherein thepolymer dispersion comprises a latex.
 65. The method of claim 59,wherein the polymer dispersion comprises a styrene-butadiene.
 66. Themethod of claim 59 wherein the polymer dispersion comprises apolyurethane dispersion.
 67. The method of claim 59 wherein the polymerdispersion comprises polyvinyl chloride, an acrylic rubber, abutyl-containing polymer, a chlorosulfonated polyethylene rubber, afluoroelastomer, or a polyisoprene.
 68. The method of claim 59, whereinthe polymer dispersion comprises a polymer and a surfactant dispersed ina liquid carrier.
 69. The method of claim 59, wherein the polymerdispersion comprises up to about 80% by weight of the polymer.
 70. Themethod of claim 59, further comprising forming the polymer dispersion bysubjecting a mixture of the polymer in the first liquid carrier to ashearing process.
 71. The method of claim 59, wherein the clay mineralcomprises montmorillonite.
 72. The method of claim 59, wherein the claymineral comprises bentonite.
 73. The method of claim 59, wherein theclay mineral comprises hectorite, saponite, attapulgite, beidelite,stevensite, sauconite, nontronite, Laponite, or sepiolite.
 74. Themethod of claim 59, wherein the mineral clay comprises hydrotalcite. 75.The method of claim 59, wherein the clay mineral dispersion comprisesbetween about 1 to about 10% by weight of the clay mineral.
 76. Themethod of claim 59, wherein forming a clay dispersion comprisessubjecting a mixture of the clay mineral in the liquid carrier to a highshear process.
 77. The method of claim 59, wherein the clay-polymerdispersion comprises up to about 90% by weight of clay mineral withrespect to the weight of polymer in the clay-polymer dispersion.
 78. Themethod of claim 59, wherein the clay-polymer dispersion comprises up toabout 30% by weight of clay mineral with respect to the weight ofpolymer in the clay-polymer dispersion.
 79. The method of claim 59,wherein the clay-polymer dispersion comprises up to about 10% by weightof clay mineral with respect to the weight of polymer in theclay-polymer dispersion.
 80. A polymer nanocomposite prepared by themethod comprising: forming a clay mineral dispersion by adding a claymineral and an onium compound to a liquid carrier, wherein the oniumcompound is present in excess of the cation exchange capacity of theclay mineral such that a portion of the onium compound present is notbound to the clay mineral; combining the polymer dispersion with theclay mineral dispersion to form the polymer nanocomposite.
 81. Thepolymer nanocomposite of claim 80, wherein the onium compound comprisesa quaternary ammonium compound.
 82. The polymer nanocomposite of claim80, wherein the onium compound comprises a quaternary ammonium compoundhaving the structure:

wherein R₁, R₂, R₃, and R₄ are independently alkyl groups, aryl groupsor arylalkyl groups, and wherein at least one of R₁, R₂, R₃, or R₄ is analiphatic group derived from a naturally occurring oil.
 83. The polymernanocomposite of claim 80, wherein the amount of onium compound is up toabout 3 times the cation exchange capacity of the clay mineral.
 84. Thepolymer nanocomposite of claim 80, wherein the method further comprisesforming a polymer dispersion by adding a polymer to a liquid carrier.85. The polymer nanocomposite of claim 80, wherein the polymerdispersion comprises a latex.
 86. The polymer nanocomposite of claim 80,wherein the polymer dispersion comprises a styrene-butadiene.
 87. Thepolymer nanocomposite of claim 80, wherein the polymer dispersioncomprises a polyurethane dispersion.
 88. The polymer nanocomposite ofclaim 80, wherein the polymer dispersion comprises polyvinyl chloride,an acrylic rubber, a butyl-containing polymer, a chlorosulfonatedpolyethylene rubber, a fluoroelastomer, or a polyisoprene.
 89. Thepolymer nanocomposite of claim 80, wherein the polymer dispersioncomprises a polymer and a surfactant dispersed in a liquid carrier. 90.The polymer nanocomposite of claim 80, wherein the polymer dispersioncomprises up to about 80% by weight of the polymer.
 91. The polymernanocomposite of claim 80, wherein the method further comprises formingthe polymer dispersion by subjecting a mixture of the polymer in aliquid carrier to a shearing process.
 92. The polymer nanocomposite ofclaim 80, wherein the clay mineral comprises montmorillonite.
 93. Thepolymer nanocomposite of claim 80, wherein the clay mineral comprisesbentonite.
 94. The polymer nanocomposite of claim 80, wherein the claymineral comprises hectorite, saponite, attapulgite, beidelite,stevensite, sauconite, nontronite, Laponite, or sepiolite.
 95. Thepolymer nanocompite of claim 80, wherein the clay mineral compriseshydrotalcite.
 96. The polymer nanocomposite of claim 80, wherein theclay mineral dispersion comprises between about 1 to about 10% by weightof the clay mineral.
 97. The polymer nanocomposite of claim 80, whereinthe method further comprises forming a clay dispersion by subjecting amixture of the clay mineral in the second liquid carrier to a high shearprocess.
 98. The polymer nanocomposite of claim 80, wherein theclay-polymer dispersion comprises up to about 90% by weight of claymineral with respect to the weight of polymer in the clay-polymerdispersion.
 99. The polymer nanocomposite of claim 80, wherein theclay-polymer dispersion comprises up to about 30% by weight of claymineral with respect to the weight of polymer in the clay-polymerdispersion.
 100. The polymer nanocomposite of claim 80, wherein theclay-polymer dispersion comprises up to about 10% by weight of claymineral with respect to the weight of polymer in the clay-polymerdispersion.